Hi everybody,
This is question both related to a job retrofit issue, but also for hobby project applications for reusing old cores from PCBs, old appliances etc.,
I want to better understand how to reuse an iron core for inductor rewinding and application with different AC input voltages.
Reviewing on magnetics and inductor desing basic principles, I got the following conclusions that I would appreciate your comments, or corrections if any are wrong:
1- Inductor base voltage rating and inductance values are (V, L, N).
Base axiom is: core shall keep original magnetic flux to avoid saturation.
2- If changing inductor voltage, Vnew=V*K. For keeping flux, acc. Faraday´s law for inductor, V=-N d(flux)/dt. Number of turns N then should be proporionally changed, to keep flux amplitude constant: N_new=N*K.
3- Considering same flux, no saturation occurs, so no need for airgap adjusting or similar.
Then, inductanace will be L_new=L(Nnew^2)=L*K^2 acc. standard inductance formulae.
4- Stored energy, considering the inductor as sole load for the source:
current will be I_new=Vnew/Znew=V*K/(L*K^2)=V/(L*K)=I/K, as impedance is linear with L.
Then stored energy will be the same: E= 0,5*Lnew*Inew^2 = 0,5*L*K^2*(I/K)^2 = 0,5*L*I^2,
Any comment is welcomed,
Regards
This is question both related to a job retrofit issue, but also for hobby project applications for reusing old cores from PCBs, old appliances etc.,
I want to better understand how to reuse an iron core for inductor rewinding and application with different AC input voltages.
Reviewing on magnetics and inductor desing basic principles, I got the following conclusions that I would appreciate your comments, or corrections if any are wrong:
1- Inductor base voltage rating and inductance values are (V, L, N).
Base axiom is: core shall keep original magnetic flux to avoid saturation.
2- If changing inductor voltage, Vnew=V*K. For keeping flux, acc. Faraday´s law for inductor, V=-N d(flux)/dt. Number of turns N then should be proporionally changed, to keep flux amplitude constant: N_new=N*K.
3- Considering same flux, no saturation occurs, so no need for airgap adjusting or similar.
Then, inductanace will be L_new=L(Nnew^2)=L*K^2 acc. standard inductance formulae.
4- Stored energy, considering the inductor as sole load for the source:
current will be I_new=Vnew/Znew=V*K/(L*K^2)=V/(L*K)=I/K, as impedance is linear with L.
Then stored energy will be the same: E= 0,5*Lnew*Inew^2 = 0,5*L*K^2*(I/K)^2 = 0,5*L*I^2,
Any comment is welcomed,
Regards
